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The antimicrobial activity of the ethanol extract of propolis (EEP) from the stingless bee, Tetragonula biroi Friese, was screened for activity against Escherichia coli, Pseudomonas aeruginosa,Bacillus cereus,Candida krusei, Staphylococcus aureus, and Penicillium chrysogenum using the disk diffusion method and agar-well assay. The highest inhibitory activities of EEP was observed at 30% (w/v) against Bacillus cereus (12.78 ± 1.92 mm), followed by Staphylococcus aureus (10.22 ± 0.83 mm), Penicillium chrysogenum (13.33 ± 2.40 mm), and Candida krusei (6.00 ± 0.00 mm) compared to the other concentrations – 10% (v/v) and 20% (v/v) of EEP. The antimicrobial activity of 30% w/v EEP against P. chrysogenum and C. krusei was comparable to mycostatin at 13.67 ± 0.58 and 6.33 ± 0.58 mm, respectively. The EEP was found to have no effect on Escherichia coli and Pseudomonas aeruginosa. Considered as a natural product, propolis has the potential to be a substitute for synthetic antimicrobial compounds commonly used in commercial products such as soaps. [ABSTRACT FROM AUTHOR]

Abstract: The effectiveness of gamma radiation in inactivating the Philippine isolate of Paenibacillus larvae was investigated. Spores of P. larvae were irradiated at incremental doses (0.1, 0.2, 0.4, 0.8 and 1.6kGy) of gamma radiation emitted by a 60Co source. Surviving spores were counted and used to estimate the decimal reduction (D 10) value. A dose of 0.2kGy was sufficient to inactivate 90% of the total recoverable spores from an initial count of 105–9×103 spores per glass plate. The sterilizing effect of high doses of gamma radiation on the spores of P. larvae in infected hives was determined. In this study, a minimum dose (D min) of 15kGy was tested. Beehives with sub-clinical infections of AFB were irradiated and examined for sterility. All the materials were found to be free of P. larvae indicating its susceptibility to γ-rays. After irradiation, there were no visible changes in the physical appearance of the hives’ body, wax and frames. Thus, a dose of 15kGy is effective enough for sterilization of AFB-infected materials. [Copyright &y& Elsevier]